The present invention relates to an operator for opening and closing a door or a window, comprising a motor-driven double-chain operator with two chain members, both flexible in one direction only, said chain members being accommodated in the closed position of the door or the window, in a substantially closed operator housing, in which the chain members are individually in engagement with a rotating drive member in communication with outlet openings for the chain members, and separate chain paths connected therewith, from which the chain members may be joined in a back-to-back arrangement for the provision of a rigid operator member, the two chain members being composed of chain links having hinge parts with parallel rotational axes oriented transversely to the direction of propagation of the chain member in the associated chain path in the operator housing for engagement with neighbouring chain links in the same chain member and having a back surface provided with zip-like engagement members for engagement with corresponding engagement members on the back surfaces of adjacent chain links in the other chain member for securing the chain members in the joined operator member against displacement transversely to the opening/closing direction, whereby the substantially closed operator housing and coupled free ends of the chain members are connected with profile members of the frame and sash structures of the door or the window, said profile members being positioned opposite one another and extending transversely to the opening/closing direction of the door or the window.
GB-A-422,781 and U.S. Pat. No. 5,271,182 disclose window operators of this type with a double-chain operator, in which the two chain members in the housing are guided in separate chain paths, which throughout their entire length are bound to extend in a common plane, whereby a desired length of the operator member composed of the chain members requires a comparatively bulky housing.
On this background, the object of the invention is to provide a door or window operator of the type described, by means of which the operator housing for a given desired length of the operator member may be made substantially more compact.
To meet this object a door or window operator according to the invention is characterized in that in each chain member the hinge parts of the chain links are designed such that during propagation of the chain member in the operator housing a mutual displacement is allowed between neighbouring chain links in the chain member in the direction of the rotational axes, and that the separate chain paths only in a part of the housing extend in a plane common with the outlet openings.
Due to this mutual displaceability of the chain links the chain paths are not bound to extend in one plane, but may extend in two or more levels partly overlapping one another, the chain members being movable between such different levels during their propagation in the chain paths, for instance over ramp like connecting sections. Hereby, a substantially bigger freedom of choice in respect of the design of the operator housing is obtained and the possibility of a more compact design of the housing for a given desired length of the operator member composed of the chain members.
It should be noted in this connection that propagation of a single-chain in two levels in an operator housing is known per se from EP-BL-0 600 105 and EP-B1-0 620 890.
In a preferred embodiment the hinge parts in each chain link comprise a pin member of substantially hook-shaped cross section and a guide member formfitting therewith, said guide member being open at at least one of a pair of opposite side faces of the chain link.
The mutual displaceability of the chain links in each of the two chain members has the effect that the individual chain links in a chain member are not in themselves in secured connection with the neighbouring chain links, but such a secured connection is established partly by the design of the operator housing and the chain paths, which limit the mutual displaceability of the chain links, partly through the locking engagement between two chain members when joined into the rigid operator member.
By a comparatively simple and appropriate design of the operator housing, said common plane may be formed by a lower housing part, one chain path extending in its entirety in said lower housing part, whereas the second chain path over a substantial part of its length extends in an upper housing part overlapping said one path and continuing in said common plane via a ramp.
Particularly in case of comparatively big and heavy windows, it would normally be preferred to use more than one operator. By means of an alternative embodiment of a door or window operator according to the invention, it becomes possible to place such operators with a compact design of the housing appropriately at the corners between the bottom and side members of the frame and sash structures due to the fact that outside said part of the housing the chain paths are helically shaped with an axis substantially perpendicular to said common plane. The chain paths may then be accommodated in chain storages which are mounted on the frame side members or possibly built into them.
Further advantageous embodiments are stated in the dependent claim.